An organic electroluminescent element has features such as being self-luminous, exhibiting relatively highly efficient light-emitting characteristics, and being able to emit light of various tones. Organic electroluminescent elements are expected to be applied as a display device (such as a light-emitting body for a flat-panel display) and as a light source (such as a backlight of a liquid crystal display apparatus and for illumination), and they have been already put into practical use in some field.
Here, as a light emission device including an organic electroluminescent element, a light emission device shown in FIG. 30 is proposed in JP2011-165444 A (hereinafter referred to as Document 1).
A light emission device as shown in FIG. 30 includes a transparent substrate 110, an organic EL element 120 on a first surface of the transparent substrate 110, and an uneven structure 130 that is on a second surface of the transparent substrate 110 and is configured to suppress a reflection, at the second surface, of light emitted from the organic EL element 120. The light emission device further includes a package substrate 140 disposed over the second surface of the transparent substrate 110 and a protector 150 covering an opposite side of the organic EL element 120 from the transparent substrate 110, the protector 150 being for preventing a moisture from reaching the organic EL element 120. In the light emission device, a space 170 is present between the uneven structure 130 and the package substrate 140.
In the organic EL element 120, an anode 122 and a cathode 124 include portions extended to regions of the first surface of the transparent electrode 110. The regions do not overlap a light-emitting layer. Parts of the extended portions of the anode 122 and the cathode 124 function as pads 122a and 124a, respectively.
Furthermore, in the light emission device, the package substrate 140 has a face opposite the transparent substrate 110, and external connection electrodes 142 and 144 are provided on this face of the package substrate 140. The external connection electrodes 142 and 144 are connected to pads 122a and 124a via connection parts 132 and 134, respectively. The connection parts 132 and 134 are bonding wires.
The protector 150 is formed of a glass substrate. The protector 150 formed of the glass substrate is bonded to the package substrate 140 with a bond 180 formed of fritted glass.
In the light emission device as shown in FIG. 30, electrical connections between the pad 122a and the external connection electrode 142 and between the pad 122b and the external connection electrode 144 are made through the connection parts 132 and 134 which are bonding wires, respectively. Therefore, an area of a non-light emitting portion is increased, and this causes to depreciate the design.